MONTPELIER - Vermont’s 911 emergency calling system — and state oversight of it — are coming under scrutiny after at least four outages in less than two years.

Outages in November 2014, January of this year and two this past summer are raising concerns about the reliability of a system that can mean life or death.

“It’s literally sheer luck that somebody hasn’t died or been permanently maimed during these outages,” said Stephen Whitaker, a resident who has followed closely the state’s investments in communications technology. “You’re playing Russian roulette with the system’s reliability.”

Meanwhile, officials in the Public Service Department are resisting calls from some quarters to open up a comprehensive investigation of what has been ailing the 911 system. The department is asking the Public Service Board to limit its review to an outage on Jan. 5. It maintains the one in 2014 has been resolved and the two from the summer are the jurisdiction of the Enhanced 911 Board which oversees the 911 system.

“We are investigating what we believe the law allows us to investigate, and it’s our understanding the 911 board is in the process of hiring an expert to investigate the summer outages,” James Porter, the department’s director of telecommunications and connectivity, said in an interview.

He explained that the 2014 and January outages had involved the underlying telephone network operated by FairPoint Communications, Vermont’s main landline phone company, which is subject to the jurisdiction of the department and the Public Service Board. The summer outages occurred within the 911 system that is attached to but separate from the underlying phone network, Porter said.

As it happens, FairPoint is the vendor on the 911 system as well. Vermont entered into a 5-year, $11.2 million contract with FairPoint to manage the system in late 2014.

FairPoint spokeswoman Angelynne Beaudry said in an email the company had worked to resolve the outages and to prevent more. “We want Vermonters to know that we are committed to providing excellent, reliable E-9-1-1 service and continue to work closely with the state to deliver it,” she wrote.

Whitaker has joined with Charles Larkin, a retired telecommunications engineer formerly with Porter’s department, and two lawmakers to call for a broader investigation by the Public Service Board of the overall operations of the 911 system.

Reps. Kathleen Keenan, a Democrat, and Mike Marcotte, a Republican, wrote to Porter’s boss, Public Service Commissioner Christopher Recchia, to request a broader review. They said they were aware of the department’s jurisdictional concerns, but after listing concerns about the 911 system, said they “should be addressed in one comprehensive investigation to the fullest extent possible.”

The Public Service Board now has opened two cases: the one requested by the department looking at the Jan. 5 outage, and another looking at all the outages and the system’s underlying reliability.

As the state and FairPoint were working to finalize their contract in late 2014, Whitaker and Larkin began urging that the Enhanced 911 Board hire an engineering consultant to vet what FairPoint was offering, according to minutes from a December 2014 meeting of the board and legislative testimony. The board is in the process of hiring an outside engineering consultant now.

“It is our opinion that all state requirements related to the issuance of the (request for proposal), evaluation of the proposals and the review of the resulting contract were met prior to contract signing,” Barb Neal, executive director of the Enhanced 911 Board, said in an email.

Following the summer outages, the board “feels it is practicing due diligence by hiring an expert consultant to ensure the system is meeting all contractual requirements and industry best practices,” she added.